The following analysis focuses on crude oil , not on oil equivalent (boe), which includes gas. Contrary to Eagle Ford and some formations, crude oil production dominates in the Bakken, representing more than 80% of total energy production. ND stands for North Dakota. The wells considered are wells who had their peak production in 2014. The peak month production is usually labeled IP30.
The maximum production of a well is normally near the production start, often after a short ramp up phase of a few months. Because the IP30 period usually doesn’t start at the 1st of a month, real IP30 is generally spreads across 2 calendar months. Database numbers are based on calendar months. Initial production is declining fast, the calendar month based IP30 numbers are a therefore a little bit lower than the real IP30 numbers and calculated decline rates from database numbers are logically also somewhat lower than reality. The difference has no impact on cumulative production numbers and well economics. All the following IP30 values are based on calendar months.
Various publications have published different IP30 numbers for average Bakken productivity. To get the most correct data, a database derived from the official NDIC well specific monthly production values is used. To be sure to really catch the month with peak production, several months (ideally one year) of post completion date production numbers should be available.
IP30 – The problem with confidential wells
If unadjusted raw production data from the above mentioned database are used, the average IP30 for the more than 2000 wells with IP30 in 2014 is calculated to around 470 bpd. One problem with monthly raw data is that the data of the included confidential wells are not complete. Confidential well production data generally do not show data for the initial months of production, including the data for the IP30 month. Average IP30 based on raw data get results that are too low. Placing wells in the confidential category became epidemic in 2014, increasing to nearly 50% of total wells.
The complete production data of confidential wells are published with a significant delay in the yearly production statistics. But monthly runs (sales volumes) are published in the monthly statistics also for the confidential months. Statistical comparisons reveal that, at the aggregate levels presented here, the difference between runs data and production data is less than 1%.
Initially, in this chapter, confidential and non confidential wells were considered separately. But that provided little additional insight. So that differentiation has been dropped and, for a uniformed approach, the “runs” data are retained for all wells.
Production curve alignment
Another issue is that for the calculation of averages, in some publications, the well production data are aligned on the first production month, assuming that the second production month is the IP30 month, which is often not the case. That results in average IP30 values and decline rates being too low.
Only wells with laterals (horizontal wells) have been retained. The reason is that costs and economic considerations, presented in other chapters, refer to horizontal wells. In ND’s monthly well production statistics, approximately 5% of the wells having IP30 in 2014 do not figure in ND’s other lists containing only horizontal wells. The productivity of these non horizontal wells is relatively low and they have contributed less than 3% to new 2014 production.
There is usually a ramp up phase before the well reaches its IP30 month. Generally, that is occurring in the directly preceding months. For a few % of the wells, that phase extends to several months. The cumulative amount of pre-IP30 production was around 70% of IP30 production.
2014 – All Horizontal Wells – ND Bakken
The following table is included for informative reasons. It show the IP30 values for all non confidential wells (horizontal and others) and is based on production data.
2014 – All Non Confidential Wells – ND Bakken
The following chart shows the underlying well productivity distribution. The value associated with the number 400 for example means that roughly 12% of the wells hat Ip30 between 300 and 400 b/d.